1. Field of the Invention
The present invention is in the field of sporting goods and more specifically relates to a power supplying accessory that can be retrofitted to existing skateboards.
2. THE PRIOR ART
In U.S. Pat. No. 4,069,881, Shiber describes an auxiliary power unit for a skateboard. The wheels of the auxiliary power unit serve as a replacement for the rear truck of the skateboard, and in order to use his device, the skateboard must be provided with an attachment that extends about the top surface of the skateboard. Thus, Shiber's unit could not be attached to an existing skateboard without considerable modification of the skateboard.
In U.S. Pat. No. 4,073,356, Schlicht shows a skateboard in which an auxiliary power unit is mounted in the center of the skateboard. The diameter of the driving wheel is such that the wheel does not touch the pavement unless the board is loaded. It would appear that this power unit cannot be mounted to a skateboard without permanently altering the skateboard.
In U.S. Pat. No. 4,094,372, Notter shows an auxiliary power unit that is mounted to the rear truck of the skateboard and which supplies power to the rear wheels of the skateboard. In contrast, in the present invention, the auxiliary power unit adds a drive wheel to the skateboard.
None of these patents shows the present invention which has unique advantages.